<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>写⼀个 JS 函数，打印当前⻚⾯窗⼝的所有内容</title>
</head>

<body>
  <p>nnjjjj</p>
  <button onclick="aa()">打印</button>
  <script>
    function aa() {
      window.print()
    }
  </script>
</body>

</html>